cpython/Include/pyhash.h at main · https-github-com-nzysoft/cpython · GitHub

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#ifndef Py_HASH_H

#define Py_HASH_H

#ifdef __cplusplus

extern "C" {

#endif

#ifndef Py_LIMITED_API

/* hash function definition */

typedef struct {

Py_hash_t (*const hash)(const void *, Py_ssize_t);

const char *name;

const int hash_bits;

const int seed_bits;

} PyHash_FuncDef;

PyAPI_FUNC(PyHash_FuncDef*) PyHash_GetFuncDef(void);

#endif

/* Cutoff for small string DJBX33A optimization in range [1, cutoff).

* About 50% of the strings in a typical Python application are smaller than

* 6 to 7 chars. However DJBX33A is vulnerable to hash collision attacks.

* NEVER use DJBX33A for long strings!

* A Py_HASH_CUTOFF of 0 disables small string optimization. 32 bit platforms

* should use a smaller cutoff because it is easier to create colliding

* strings. A cutoff of 7 on 64bit platforms and 5 on 32bit platforms should

* provide a decent safety margin.

#ifndef Py_HASH_CUTOFF

# define Py_HASH_CUTOFF 0

#elif (Py_HASH_CUTOFF > 7 || Py_HASH_CUTOFF < 0)

# error Py_HASH_CUTOFF must in range 0...7.

#endif /* Py_HASH_CUTOFF */

/* Hash algorithm selection

* The values for Py_HASH_* are hard-coded in the

* configure script.

* - FNV and SIPHASH* are available on all platforms and architectures.

* - With EXTERNAL embedders can provide an alternative implementation with::

* PyHash_FuncDef PyHash_Func = {...};

* XXX: Figure out __declspec() for extern PyHash_FuncDef.

#define Py_HASH_EXTERNAL 0

#define Py_HASH_SIPHASH24 1

#define Py_HASH_FNV 2

#define Py_HASH_SIPHASH13 3

#ifndef Py_HASH_ALGORITHM

# ifndef HAVE_ALIGNED_REQUIRED

# define Py_HASH_ALGORITHM Py_HASH_SIPHASH13

# else

# define Py_HASH_ALGORITHM Py_HASH_FNV

# endif /* uint64_t && uint32_t && aligned */

#endif /* Py_HASH_ALGORITHM */

#ifdef __cplusplus

}

#endif

#endif // !Py_HASH_H

cpython/Include/pyhash.h at main · https-github-com-nzysoft/cpython · GitHub

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